CAVE JUNCTION, Ore.  "You want to try a bat hang?" Tim asks and flips over in his harness. His feet point straight up.

We're about halfway up a 60-foot black walnut, dangling from a combination of ropes, knots and carabiners. Tim has been doing this for 13 years; I've been at it about 24 hours. What the heck. I flip.

Oregon is upside-down, and this, this is all the joy of childhood, of knobby knees thrown over a branch, of hair dangling toward the grass.

The view  even right side up  is worth the work it took to get here.

I'm high enough to see over the roof of the nearby house to where the blue-hued Siskiyou Mountains peek over a dark, jagged line of evergreen treetops. If I could turn a bit to my right, I might see Redwood Highway (U.S. Hwy. 199), the main drag of Cave Junction, lined with drive-through espresso stands, burger joints and, as it disappears, family campgrounds that now house giant RVs.

Cave Junction is on the hot eastern side of the Coastal Range. If you're driving north from California, you feel the state line coming: It's where the redwood trees end. Visitors might come to the area to see Oregon Caves National Monument or to raft the wild Rogue River or to camp or hike in the endless acres of national forest or to spend the night in a treehouse, of which there are several in the area.

Me, I came to learn how to climb trees.

Looking up

I didn't really know what I was getting into when I enrolled in this basic tree climbing course at the recently established Tree Climbing Northwest school. Enticed by a radio interview with an L.A. climber, I found some schools online and made some calls. After receiving sufficient assurances that I didn't need Spider-Man-like upper-body strength, I signed up for a class last June.

I meet Tim "Tengu" Kovar when I get to his house in Cave Junction. Tim's a big guy, 6 feet, 3 inches, and exudes an easygoing warmth. He started climbing trees in 1993 while working for an Atlanta-area tree surgeon.

His boss, it turned out, was using arborists' techniques to take people up into trees for fun on the weekends. He recruited Tim as a teacher, and after a few years, Tim put down his chain saw for good. In 2005 he moved to Oregon and started his own school, Tree Climbing North-west.

I've signed up for a 2 1/2-day session. There's a lot to learn; my only classmate, Karen, is staying a full week to be trained in two climbing styles, plus rigging hammocks and stuff. I'll just learn the basic doubled-rope technique. But before any lessons or quizzes, Tim takes us to meet Ed.

Ed is our other teacher: a 60-year-old black walnut tree with wide-spread limbs.

I had imagined us deep in a forest, but in fact we're in the middle of a flat plain along the Illinois River. There's a farm/vineyard going to seed next door and a growing subdivision nearby. From Tim's, we walk down a dirt road and find ropes already in the tree.

We learn an easy first knot, the triple crown, which creates foot loops. Then we don helmets and harnesses that sort of resemble those used for rock climbing but are much sturdier and padded. Finally we secure our harnesses to loops in the ropes using locking O-ring carabiners, and start up.

Skybound

Doubled rope technique is simple but magical. A long rope  150 feet or so  is looped over a high branch. At one end is a loop (to attach to your harness) and a Blake's hitch, a knot that connects to the dangling half of the rope, called the downline. The Blake's hitch grips the downline almost like a powerful fist. The magic is that a Blake's hitch will slide upward, lock in place, and release only when you pull down on the top of the knot.

Once everything is in place, we're not so much tree climbing as knot sliding. The strength is in your legs, not your arms.

Here's how it works: My foot loops and Blake's hitch are both attached to the downline. I stand up in the loops, slide the Blake's hitch upward, then sit back in my harness and the hitch holds me in place.

So I slide my foot loops up farther, stand up and slide the hitch up again. Repeat until in the tree canopy.

Apparently there are people who climb trees competitively, racing up into the branches. But that whole conquer-the-tree mentality isn't Tim's thing; he's about reconnecting people with nature one tree climber at a time.

It's my bad luck to be here during a record-setting heat wave. We spend the mornings, thankfully, in the shade of two giant Douglas firs learning about knots and gear. Over and over we tie and untie, tie and untie, trying to get the motions into our muscle memory. We practice until we can tie an entire system of knots with our eyes closed.

There are no ropes waiting for us when we get to Ed on the second and third days. We have to toss a beanbag attached to a light throwline over the high-up branch we want to use as our climbing anchor. Then we tie the heavy-duty arborist rope to the throwline to pull it and a cambium saver  a tube that keeps the tree from getting rope-burned  into place.

It's not too difficult to prepare to ascend while standing on the ground. But changing over to another branch while in the tree is a skill I never master. From a perch, we have to throw the dangling end of the downline (or another throwline) over the next branch, tie a whole new set of knots, hook the harness in, and switch over. As we practice, we're not really climbing farther up the tree but moving around in it.

We're less like monkeys and more like sloths. I have bad aim, and I'm slow to puzzle out what the next step should be. It's as much a logic puzzle as a physical challenge.

On the second full day, Tim is much more hands-off. He's watching, though, and closely.

Earthbound

I'm about parallel with the tree boat, so I have to swing over, letting out just enough slack to reach it, but not drop below it. I get only my feet in and wind up dangling in a pose that is Cirque du Soleil gone bad. Tim grabs my feet from the other side and pulls me into the tree boat.

It's late in the day, 6-ish. The sun is coming through the feathery leaves of the black walnut. The harness isn't digging into my thighs. No rope is burning my hands. In a picture I see of myself later, I look giddy, red-faced. I'm grinning like an 8-year-old.

Too soon it's time to come down, and while it feels good to stand and walk, I feel undeniably earthbound.